(1) Field of the Invention
The present invention relates to sensors for fast and easy deployment in electroencephalogram acquisition and monitoring applications, including consciousness and seizure monitoring. The present invention further relates to electrodes for measuring biopotentials. The present invention further relates to groups or sets of sensors having individual features which facilitate their fast and correct placement and use and/or hinder or preclude their incorrect placement and use, without requiring extensive preparation of a patient's skin.
(2) Description of Related Art
Consciousness monitoring encompasses the field that uses measurements of biopotentials or other biological signals to gauge the level of consciousness or alertness of a subject or patient, especially in applications such as anesthesia monitoring or testing for seizure or other brain dysfunction or injury. Consciousness monitoring is frequently based on electroencephalographic (EEG) measurements.
In a typical diagnostic or monitoring study, a set of electrodes will be applied to the subject or patient. Proper design of electrodes and their placement is often critical to the reliability, accuracy, and/or repeatability of biopotential measurements and their analysis by the sophisticated monitoring equipment into which their signals are fed; variations in electrode placement or improper electrode placement or improper electrode spacing may mar the study if the analysis equipment is dependent upon proper placement, and may even unnecessarily endanger the patient in the event that a cardiac defibrillation shock is applied to the patient during consciousness monitoring. Traditionally, sets of electrodes are used in which all of the electrodes are essentially identical to each other in appearance. This similarity in some cases can result in electrode confusion on the part of the physician or technician applying the electrodes. Common mistakes in electrode placement include a mix-up between left-side and right-side electrode placement on the patient, a mix-up between signal and ground electrodes on the patient, incorrect placement of the electrodes on the patient in relation to the optimal or desired placement sites, placement of electrodes too near to each other or too far from each other, or placement of the electrodes in wrong or sub-optimal orientations with respect to each other. Extreme cases of misplacement result in entirely different electrode placement montages being used, but even minor misplacement can have a significant impact on the study or test results since the artifact processing, feature estimation, and suppression detection methods of test equipment or study methods can be sensitive to electrode placement. For example, too-short interelectrode distance can result in very small amplitude signals resembling suppression observed in some patients. Manufacturers of consciousness monitoring equipment have introduced specific sensors to address the problem of improper electrode placement and facilitate proper signal acquisition. Previous disclosures in this field of art include U.S. Pat. No. 6,032,064 to Devlin et al., U.S. Pat. No. 6,301,493 B1 to Marro et al., U.S. Pat. No. 6,950,698 B2 to Sarkela et al., and U.S. Patent Application Publication No. 2004/0193068 A1 to Burton et al., all of which are herein incorporated by reference.
However, the need still exists for novel systems and methods which better facilitate fast and accurate electrode placement and use and/or hinder or preclude their incorrect placement and use. It is envisioned that once seizure detectors are as common appliances in workplaces and schools as are emergency cardiac defibrillators today, it will be critical for persons of no special training to perform fast and accurate electrode placement. It is therefore an object of the present invention to provide a novel electrode kit for easy and fast deployment in electroencephalogram acquisition and monitoring applications.